[AMPS] Parasitic suppressors

[Rich Measures]

>
>On Sun, 31 Aug 1997 07:08:12 +0200 lars.harlin@pocab.se (Lars Harlin)
>writes:
>>Have followed the discussions abt VHF parasitics on the reflector and 
>>other media.  Has anyone tried using ferrit in a suppressor? 
>>
>>Lars / SM3BDZ
>>
>
>The only amps I am aware of were the Heath SB-230 ...

In the SB-230, the ferrite bead is only in series with the HV-RFC.  It is 
not in series with the anode's VHF-resonant circuit - i.e., the circuit 
which supports oscillation.   

> ...  The Heath was a disaster and blew many tubes. 

Amen, Carl.  With no VHF suppressor in the anode's VHF-resonant circuit, 
the life of a high VHF gain tube is often brief.  The AL-1500 is another 
such amplifier.  A number of owners told me that their's went through a 
number of 8877s during the first year.  One of them discovered the 
seemingly-bizarre technique for making some gold-sputtered 8877s useable. 
  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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